He was three years younger than her, and when she went to kindergarten, he was still making trouble at home, and they didn't know each other at that time; when she went to elementary school, he started going to kindergarten, and they still didn't know each other; she was in sixth grade, and he was in third grade, and they had already played together with many children of the same age; she graduated from junior high school, and he graduated from elementary school, and it seemed like they lost contact overnight. , He already has his own circle, and she is still with people with similar interests; maybe the girl is a bit precocious and finds it boring to play with children, or maybe they both overestimated the friendship they had when they played together. He just thinks she is a pretty sister, and she just thinks he is a very obedient younger brother. In fact, there is not much interaction...